Acid resistant film forming dental composition and method of use

ABSTRACT

A method of forming a solution of oxalic acid potassium salt dihydrate, useful for desensitizing dentin, comprising the steps of admixing an effective amount of oxalic acid potassium salt dihydrate in water having a pH of 2.0-4.0, heating the solution at a temperature range from 85° F. to 100° F. until a suspension is formed, ultrasonically vibrating this suspension for an effective amount of time and frequency to reduce the oxalic acid potassium salt dihydrate to a particle size of 1 to 10 microns.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] Individuals often report an immediate increase in dentinpostoperative hypersensitivity or pain to sudden extremes of thermalstimuli to either a particular tooth or a group of teeth. This may occurfollowing either the replacement of a restoration due to a recurrentcarious lesion subjacent to a previously placed restoration, the initialplacement of an existing amalgam alloy or a tooth colored resincomposite restorations or following the bleaching of teeth with power(light, heat or other) assisted forms of tooth whitening systems.Patients may simply be cautioned by the dentist to be aware of animmediate increased feeling of pain to a rapid jet of air, cold drinks,to chewing forces of occlusion or to other factors such as acidic foods.Stimuli, such as cold water, cool air, osmotic gradient shifts, or sweetor acidic solutions at the cavosurface margin of a restoration have allbeen shown to cause an immediate increase in the dentin pain response.Dentists may simply call this phenomenon as patient dentin pain(postoperative hypersensitivity/DPH) or simply dental discomfort. Oftenpatients are told by the dentist to simply wait a few days or weeks andthat the pain of discomfort will become less and less, and eventuallythat it should go away.

[0003] The acute, sharp, piercing pain of dentin pain is often a fairlycommon complaint among many patients who have recently received anamalgam alloy or resin composite restoration in vital dentin that hasbeen treated with a conventional dentin liner such as a calciumhydroxide Ca(OH)₂ material such as Dycal® or Life®. Dentin postoperativehypersensitivity generally occurs with the normal physiologicalbreakdown of the smear layer or its removal at the cavosurface margindue to oral fluids which reach an acidic pH of 2.7 to more neutral at pH6.0.

[0004] If the dentist uses any type of instrumentation, for example,rotary instrumentation with a drill or bur, scraping or polishing withany sort of hand instrument, will leave a layer of debris on the toothsurface called a smear layer. The breakdown of the smear layer byphysiological action or by the dentist, opens and exposes the dentinaltubule complex to a bi-directional flow of fluids from the dental pulp(Pashley, 1981 Arch. Oral. Biol. 26: 703-706). It is this increasedbidirectional fluid flow which is responsible for the patients' dentinpostoperative hypersensitivity to cold or rapid air flow.

[0005] Many patients experience dentin postoperative hypersensitivitywhen an existing amalgam alloy or a resin composite restoration and itsunderlying Ca(OH)₂ base of Dycal® or Life® washes out or is removed andthe dentin loses its biological seal or simply feel the pain fromdiscomfort due to premature occlusal contact or thermal or coldextremes.

[0006] The physiological mechanism for dentin pain following placementof either an amalgam alloy or a resin composite restoration has beenexplained as being due to the breakdown or loss of the smear layer whichthen results in an immediate increased flow of pulpal fluids through itsmicro channel complex (Pashley, et al. 1984 Arch. Oral. Biol. 29:65-68).This increase in flow may be 94% greater than the normal physiologicalflow of fluids through the normal dentin substrate.

[0007] The present invention relates to the use of an acid resistantfilm forming liner material that occludes the dentinal tubules todecrease dentinal sensitivity, acid penetration and discomfort.

[0008] 2. Summary of the Related Art

[0009] The aforementioned Pashley et al., articles disclose thehydrodynamic theory of flow and displacement of the contents of dentaltubules under various conditions. Pain stimuli is transmitted to nervestructure by hydrodynamic movement of force in the tubules within thedentin. Prior art methods of alleviating pain during dental restorationprocedures include preparing a cavity in a tooth to receive restorativematerial with a cavity liner or cavity varnish. The material allegedlydecreases the permeability of the dentin to other materials placed inthe cavity during this restoration in addition to blocking the attack ofany microleakage, that is, contaminants from the oral fluids that mayattempt to penetrate the cavity in the event that the restorativematerial permits microleakage around its margins with the tooth. Priorart cavity varnishes frequently contain organic gums dissolved inorganic solvents. The organic solvent evaporates leaving a film of theorganic gum on the dentin.

[0010] These cavity lining agents are composed primarily of water andsoluble organic materials which is often placed on a liquid layer thatcovers the surface of the dentin without any bonding. This may weakenany adherence of the cavity varnish to the tooth surface and may causeleaking.

[0011] A natural cavity liner is microcrystalline debris which is foundin the surface of dentin which is cut and is referred to as a smearlayer. The smear layer occludes the orifices of the dentinal tubules tothe point where bacteria cannot access the tubules. However, the smearlayer is often destroyed due to the acidity in the oral cavity and thepresence of microleakage around the filling material which is in contactwith a cavity varnish.

[0012] The prior art also includes the use of oxalate salts todesensitize hypersensitive dentin or cementum surfaces on teeth, forexample, as disclosed in U.S. Pat. No. 4,057,621. U.S. Pat. No.4,538,990 discloses a two-step method using different oxalate acidssalts to decrease the permeability of a dental cavity prepared forreceiving a restorative material. The method involves sequentialapplication of the oxalate salts to the smear layer. First, a 1 to 30%weight to volume neutral oxalate salt solution, for example, dipotassiumoxide, is applied and then followed within one or two minutes by anapplication of 0.5 to 3% weight to volume percent of an acidic oxalatesolution, such as monopotassium mono hydrogen oxalate. The neutraloxalate forms large calcium oxalate crystals over the dentin surface andthe acid oxalate forms smaller crystals around the previouslyprecipitated larger crystals to form a uniform layer of crystals.

[0013] U.S. Pat. No. 2,746,905 discloses the use of dehydroacetic acidand the soluble salts to maintain the pH of the mouth to about 5.2 toprevent the dissolution of inorganic tooth enamel material whichincludes the use of oxalate in the composition as an enamel protectiveagent to increase the resistance of the tooth to acid attack.

[0014] In contrast to the above literature and patents, the presentinvention utilizes a specific oxalic acid salt, oxalate acid potassiumsalt, dihydrate, 99% which when applied to the surface of the toothpenetrates into the tubules and fibriles of the dentin layer. The oxalicacid potassium salt dihydrate, or it may be simply referred to aspotassium oxalate dihydrate, eliminates fluid movement within thetubules and therefore limits the dentin to be incapable of transmittingpainful stimuli to the pulp in the form of fluid movement Therefore, nopain or discomfort is felt by the patient for long periods of time.

SUMMARY OF THE INVENTION

[0015] The present invention relates to a method of utilizing a solutionof oxalic acid potassium salt, dihydrate, 99% as referred to hereinafteras potassium oxalate dihydrate, to react with ionized calcium in thedentinal fluid forming an insoluble white precipitate of calcium oxalatethat includes the dentinal tubules. This action leads to decreasedpermeability of dentin, decreased acid penetration of dentin anddecreased dentinal sensitivity. The solution of potassium oxalatedihydrate contains about 1.5 to about 10% by weight oxalic acidpotassium salt dihydrate and has a pH ranging from about 2.0 to about4.0.

[0016] It is an object of the present invention to provide a method ofusing a solution of oxalic acid potassium salt dihydrate to decreasepermeability of dentin.

[0017] Another object of the present invention is to provide a method ofusing a solution of oxalic acid potassium salt dihydrate to decreasedentin sensitivity.

[0018] Another object of the present invention is to provide a method ofusing a solution of oxalic acid potassium salt dihydrate to decreaseacid penetration of dentin.

[0019] And, yet another object of the present invention is to provide asimple diagnostic test to determine if dental pain or discomfort isreversible or irreversible.

[0020] Another object of the present invention is to provide a method tosolubilize oxalic acid potassium salt dihydrate in water so that it isavailable in a dosage form to serve as a desensitizing agent

DETAILED DESCRIPTION OF THE INVENTION

[0021] The mechanism action of the potassium oxalate as well as itseffectiveness in reducing dental sensitivity had been reported byPashley, et al. in the literature, see Pashley, D. H. et. al. (1983):Dentin Permeability—Effects of Desensitizing Dentrifices In Vitro, J.Periodontol. 55:522-525; Pashley, D. H. and Galloway (1985): The Effectsof Oxalate Treatment on the Smear Layer of Ground Surfaces of HumanDentine. Arch Oral. Biol. 30: 731-737; Pashley, DH. (1989): Dentin: ADynamic Substrate—A Review. Scanning Micros 3: 161-176; Pashley, E. L.et al. (1989) Dentin Permeability and Bond Strengths after VariousSurface Treatments. Dent. Mater 5: 375-378.

[0022] Pashley, et. al. discloses a potassium oxalate form of protectivelayer of insoluble calcium oxalate on the surface of the exposed dentinthat occludes open tubules. The occlusion causes a decrease inhydroconductance and tubule permeability as well as a decrease in acidpenetration and, ultimately a reduction in dentinal sensitivity. U.S.Pat. No. 4,057,621 discloses potassium oxalate compounds useful in theinvention comprising a method of desensitizing hypersensitive dentin andcementum. In the method, a member selected from the group consisting ofa mono and di-substituted alkali metal and ammonium oxalate in anaqueous solution is applied in an effective amount to the dentin andcementum to desensitize the area. Compounds disclosed in the patentinclude the following, which are shown with their water solubility. Theyare described in the 54th and 76th Editions, Handbook of Chemistry andPhysics (1973-74 and 1995-96). Dipotassium oxalate (K₂C₂O₄.H₂O) 33.0 HotWater Solubility Potassium hydrogen oxalate (KHC₂O₄) 16.7 Hot WaterSolubility Sodium oxalate (Na₂C₂O₄) 6.33 Hot Water Solubility Sodiumhydrogen oxalate (NaHC₂O₄.H₂O) 21.0 Hot Water Solubility Lithium oxalate(Li₂C₂O₄) 8.0 Cold Water Solubility Lithium hydrogen oxalate(LiHC₂O₄.H₂O) No reading Ammonium oxalate [(NH₄)₂C₂O₄.H₂O] 11.8 HotWater Solubility Hydrogen oxalate (NH₄HC₂O₄.H₂O) No reading

[0023] The active ingredient in the present invention is oxalate acidpotassium salt, dihydrate 99% with a molecular weight of 254.19 and aformula of C₄H₃ KO₈.₂H₂O. The oxalate potassium salt, dihydrate 99% orreferred to herein as potassium oxalate dihydrate is a white crystalinepowder that is slightly soluble in water, having a solubility of 29Gm/liter. The potassium oxalate dihydrate is utilized preferably in anaqueous solution. Dissolving the potassium oxalate dihydrate in watermay be difficult under conventional practices, however, the product ofthe present invention is subjected to ultrasonic frequencies to dispersethe large crystals of the potassium oxalate in water and thereforesolubilize in water. This treatment renders the potassium dihydrate intoa particle size which is adequate and sufficient for the purposes ofthis invention. Any treatment to solubilize the potassium oxalatedihydrate in water will be satisfactory, however, the use of variablehigh frequency sound waves is preferred.

[0024] In order to prepare the product of the present invention, doubledistilled deionized water, with a water purity of 1,000,000 to 5,000,000resistance in ohms, according to standardized testing of the AmericanNational Standards Institute. The high resistance equates to highpurity. Other forms of purified water may be utilized, however, thedouble distilled deionized water is preferred. Sufficient oxalic acidpotassium salt, dihydrate 99% crystals are added to the water so thatthe amount in the final solution ranges from 1.5% to 4.0% weight tovolume. Preferably, the amount is about 2.9% by weight in the finalproduct. The water and crystals are then subjected to variable ultrahigh frequency wave action to disintegrate the crystals into very smallparticles to form a solution. This is typically accomplished by using anultrasonic cell disrupter, however, any means can be used to solubilizethe oxalic acid potassium salt, dihydrate. Preferably, an ultrasoniccell disruptor such as identified as the Branson Sonifier or equivalentcan be utilized. The sonifier converts electrical energy from a powersupply to mechanical vibration. In this apparatus, the water andpotassium oxalate dihydrate crystals are placed in a mixing containerand attached to a pumping system. The pump is started to circulate thewater in a continuous flow at about ½ liter per minute. The water andcrystals are circulated in the chamber for about 30 minutes. Thisprocess uses a variable ultra high frequency wave focused in a smallchamber directly on the crystals in the water. The mechanical vibrationmay range to 20,000 Hz. In use, the preferred vibrations provide ultrasonic disassociation at a frequency of about 16,000 Hz to about 20,000Hz at the tip of the ultrasonic horn as it disrupts and disintegratesthe crystals into very small particles so that they go into solution.The water and crystal mixture passes the ultrasonic horn multiple timeswhich continues to disintegrate the crystals into smaller particles eachtime it passes. Preferably, the particle size in the final product ofone liter approximates about 1 to 4 microns when viewed under a 100power microscope. About 60% of the particles are of this size. Theremainder of the particles may range from about 5 to about 10 microns.After solubilization, no precipitate is visible after 24 hours with theunaided human eye. Larger particle sizes are acceptable, however,particle sizes in the range of about 1 microns to 10 microns arepreferred, and most preferably the particle size is about 1 to 4microns.

[0025] The acidic solution has a pH ranging from about 2.0 to 4.0 withthe preferred range being about 2.7 to about 3.0. Most preferably, thepH is 3.0. The pH of the acidic solution is controlled by the amount ofpotassium oxalate dihydrate that is used in the formulation. The largerthe amount of the potassium oxalate dihydrate the lower the pH.

[0026] In operation, the use of potassium oxalate dihydrate is a onestep process to stop sensitivity to cold and air immediately. It is alsohelpful as a diagnostic aid to assist the dentist in differentiatingbetween reversible fluid flow in dentin and nonpulp inflammation andirreversible fluid flow which results in pulp inflammation. About 3-6drops of potassium oxalate dihydrate can be placed in a clean Dappendish using forceps so that a small, sterile cotton pallet can besaturated with the potassium oxalate dihydrate which is then gentlyrubbed or dabbed onto the affected tooth area for at least thirtyseconds. The solution may be gently rubbed around the margin or over thecrown cementum or exposed root surfaces as well as onto the exposed rootof teeth which are sensitive to cold or air stimuli. Brushing theproduct on the tooth surface is not necessary and should not beaccomplished. No rinsing is needed. After application, a gentle airdispersion may be applied to the surface to evaporate the solution fromthe area leaving a frosty white surface which is an acid resistantmineral layer that stops fluid movement or dentin hypersensitivity tocold and air stimuli. It is not necessary to blast air on the toothsurface because it could remove the solution.

[0027] The product of the present invention can be applied on preparedtooth structure such as vital dentin both before and after oral hygienetreatment for prophylaxis for cleaning and scaling. The product may beused as a one-step replacement under all crowns and inlays with veneerpreparation. It can be used on the dentin of all cavity preparation foramalgam alloys, and resin composite restoration. The acid resistant filmforming liner material can have bonding materials applied directly onits surface for binding restorative materials. It may also be applied onthe tooth surface following a bleaching procedure whether the procedureis done in a dentist's office or if the patient uses a home bleachingkit. In addition, the potassium oxalate dihydrate solution can be usedas a diagnostic tool to differentiate between acute dentinal pain andchronic pulpal pain. Acute dentin pain is generally called a reversibletooth pain. To the dentist and patient, this means that there is adefect located within the substance of the dentin and not within thenerves within the dental pulp. The problem is reversible without anyinvasive endodontic treatment. Alternatively, chronic dental pain is anirreversible stimulus which indicates that the nerves of the dentalpulpal are inflamed and must be removed by some sort of biomechanicalendodontic instrumentation. The potassium oxalate dihydrate of thepresent invention provides a simple one-step diagnostic treatment thatallows the dentist to discriminate reversible and irreversible dentalpain. When a patient complains of pain to cold and air and there are nodiagnostic features of radiographic presence of a periapicalradiolucency, fractured tooth root or other obvious clinical problemsthen the dentist may simply rub the potassium oxalate dihydrate of thepresent invention onto and around edges or cavosurface margins of thetooth restoration interface. If the patient reports an immediatecessation to dental pain then the dentist may complete the diagnosisthat the problem is fluid flow in the dentin or microleakage. This isconfirmation of reversible pulp inflammation and may be treated by therepair of the restoration and not the removal of the pulp.

[0028] In order to explain the mechanism of action of the presentinvention, the following is a description of the mode of action of thepresent invention used in, for example, a restorative procedure.However, the mode of action is similar for all applications. Acidicsolution of potassium oxalate dihyrate of the present inventioninitially serves to break down the smear layer and opens the substrateof dentin, as well as enamel and cementum. Buffering occurs to the pH ofthe potassium oxalate dihydrate and as the reaction progresses, the pHof the solution the moves toward neutrality. Simultaneously, the calciumgranular particles precipitate on the entire cavity surface in additionto any small physiological cracks which are normally present in adultenamel and or cementum of the root surface. This granular precipitate,when dried, is an acid resistant lining layer that is chemically boundto the surface as well as into the dentinal tubules of the cavity. Oncethe granular crystals are formed, the barrier effect is immediately feltby the patient. To the unaided eye, there is a slightly whitish filmthat may be seen on the surface of the cavity and tooth.

EXAMPLE I Preparation of Solution

[0029] Twenty-nine (29) grams of oxalate potassium salt, dihydrate 99%,a white crystalline substance, were added to one liter of doubledistilled deionized water in a mixing container. The container is cappedand affixed to a Branson Sonifer manufactured by Branson UltrasonicCorporation of Danbury, Conn. The feed and return hoses were connectedbetween the container and sonifer. The pump on the sonifer was startedto recirculate the water at a setting of ½ liter per minute. The soniferwas started at a setting of constant duty cycle, time on hold, outputcontrol at 0.9 or 18,000 Hz.

[0030] The water was subjected to ultrasonic disassociation orvibrations for 30 minutes. The water was allowed to set for 30 minutesand samples were taken for viewing under a 100× power microscope. Thesize of the crystals was about 10 microns.

EXAMPLE 2 Preparation of Solution With Heated Water

[0031] One liter of double distilled water was heated and mixed with astir bar in a vessel until the temperature reaches 85° F. to 100° F. Ahot plate was utilized for heating the water. Twenty-nine (29) grams ofoxalate potassium salt, dihydrate 99% was added to the vessel and mixedwith the stir bar so that the white opaque oxalate potassium saltdihydrate 99% becomes clear or relatively transparent to the unaidedeye. When the solution became relatively transparent, the potassium saltwas in suspension. The solution was then added to the sonifer asdescribed in Example 1 for ultrasonic disassociation of the oxalatepotassium salt, dihydrate 99%. It was sonicated for about 40 minutes at18,000 Hz to yield a clear solution.

EXAMPLE 3 Clinical Evaluation

[0032] To show the desensitization properties of the potassium oxalatedihydrate of the present invention, amalgam restoration patients weretreated with a commonly used, commercially available cavity varnish orthe product of the present invention prior to placement of an amalgam.Prior to anesthesia for pre-treatment evaluation and during the firstweek of treatment, the patients completed a questionnaire on pain. Thepatients were also evaluated post-operatively at one, three and sixweeks. The results of the study demonstrate a reduction inpost-operative hypersensitivity, especially cold, in patients treatedwith the potassium oxalate dihydrate of the present invention.

MATERIALS AND METHODS

[0033] A total of 65 human teeth with active carious lesions precludingeither acute or chronic dentin postoperative hypersensitivitysymptomatology were selected to be restored with the commerciallyavailable amalgam alloy Tytin(r). Only patients who had elected amalgamrestoration procedures at UAB were employed for this study. Each toothreceived a pre anesthesia evaluation for dentin postoperativehypersensitive with a cold stimulus and air jet for thermal testing. Forcold-ice testing, plastic needle covers were filled with water andfrozen in a refrigerator freezer for uses as the standardized coldstimulus.

[0034] For air stimulation, the standardized baseline air jet from asyringe was used to direct a blast of air at the offending tooth anddefective restoration. A randomized number chart was employed to selectteeth for either the Copalite® varnish controls or teeth to be treatedwith the product of the present invention, potassium oxalate dihydrate.

[0035] Amalgam Preparations

[0036] Following pre operative data collection and anesthesia, eachtooth then received a routine intracoronal Class-I or Class-II cavitypreparations.

[0037] All 65 teeth 35 intracoronal Copalite® controls and 30 teeth tobe treated with the product of the present invention, potassium oxalatedihydrate, received Class-I or Class-H cavity preparations—prepared witheither a new #245 or #330 carbide bur at ultra high speed, under waterspray and high speed evacuation. Following cavity preparation, rinsingand gentle air drying, the entire preparation surface was treated withthe Copalite® varnish without modification or removal of the smearlayer. Each control cavity was treated with three layers of copalvarnish and each layer gently air dispersed with a chip syringe beforethe following Copalite® coat was applied. A metal matrix was placed onall Class II cavity preparations and the tooth was restored toanatomical contour with the dispersed phase spherical amalgam alloyTytin®.

[0038] All other clinical preparation procedures, testing criteria andrecalls were identical to those employed with the 39 teeth treated withthe product of the present mention. An additional 30 teeth were treatedwith the product of the invention, potassium oxalate dihydrate.Following intracoronal Class-I or Class-H cavity preparations for cariesremoval, the cavity was cleaned with sterile water, gently air dispersedand the prepared cavity surface treated twice with potassium oxalatedihydrate. The potassium oxalate dihydrate solution was dispensed into aclean Dappen dish and then absorbed into a sterile cotton pellet. Theentire surface area of the cavity of prepared enamel and dentin surfacewas mechanically swabbed for approximately 2 minutes, air dispersed andagain treated as before. The surface was gently air dried, the matrixplaced and the cavity restored with Tytin®.

[0039] Prior to anesthesia for pretreatment evaluation and during the 1st week of treatment, the patient was recalled to the clinic to fill outa form as to their own perception of “feeling” or response to variousstimuli, including cold, hot, sweets, biting, and brushing. The patientwas also evaluated for postoperative hypersensitivity at one, three andsix weeks post-operatively. The subjective consideration of patients'data were collected by having the patient cross the 10 cm line at apoint where they felt their range of pain was indicated. The McGillVisual analog scale was noted at each time interval. Thermal tests forice and an air jet were administered and data recorded as for all of theprevious tests.

[0040] For base line data, each patient was evaluated for pain orsensitivity to cold and air prior to their treatment in this study. Atotal of 35 patients were treated in the control in the Copalite® groupand 30 patients were treated in the potassium oxalate dihydrategroup—for a total study group of N=65.

[0041] All data was analyzed by one-way Analysis of Variance (ANOVA) atthe 0.05 level depending on the cell sizes in our contingency table oftreatments versus responses. Differences between the various groupswithin the ANOVA was compared using the Student T test (p<0.050).

[0042] Results

[0043] Questionnaire Responses

[0044] Responses from each of the patients were recorded on separatesheets and then tabulated onto the master sheet according to theidentified criteria. The raw data were recorded from the McGill VisualAnalog Scale (MVAS) evaluation sheets. Data were recorded from allpatients. experiencing none, some or severe post-operativehypersensitivity based on the patient responses at the variousintervals, preoperative at 0 days, and post treatment 5, 7, 21 and 42days. In each case responses were reported to the various test stimuli;cold, hot, sweet, biting of percussion, and brushing and flossing.Evaluation forms were completed.

[0045] The date for each of the McGill VA scales were tabulated andrecorded on a separate sheet with the patient's name and clinical recordnumber—as a 10 centimeter straight line with no identifying marks alongits axis.

[0046] Approximately 12% of the patients experienced some sort ofpreoperative hypersensitivity, in response to questions concerningpain—mostly to the cold stimulus. However, 65% of the patients claimedsome sort of pre-operative response on the MVA scale—of which over ½ ofthese patients (52%) marked values of 0-1 mm on a scale on the 10centimeter pre-operative scale. Only 2% of the total populationexperienced any pre-operative pain greater than 5 mm on the 10centimeter MVA scale.

[0047] Following routine caries excavation, application of potassiumoxalate dihydrate or Copalite® control solutions, and placement of theamalgam restoration, patients showed a reduction in sensitivitypostoperatively. In those individuals who had received the controlCopalite® treatment, there was a 2.3% reduction in sensitivity to thevarious stimuli (especially cold), in response to direct questioning.However, among the patients treated with the potassium oxalate dihydrateof the present invention, there was an overall reduction in theirreported pain by a level of 80.3%.

[0048] The collective data from the MVA scale show a dramatic reductionin post-operative pain in those teeth which were treated with potassiumoxalate dihydrate while only 68.7% of the Copalite® patients exhibitedtemporary pain reduction post-operatively.

[0049] The data show that for the cold discriminator measurement therewas a greater reduction in overall pain reduction with Super Seal thanthe commercially available Copalite®. Furthermore, patient responses tothe MVA survey document showed the majority of individuals experiencedno post operative pain with the product of the present invention,potassium oxalate dihydrate. Overall, 25.7% of the patients treated withCopaliteg and 88.5% of those patients' teeth treated with potassiumoxalate dihydrate were pain free following the first procedure.

[0050] Complete test results are shown in FIG. 1. The product of theinvention is defined as Super Seal in the table.

[0051] It should be understood that the foregoing disclosure emphasizescertain specific embodiments of the invention and that all modificationsor alternatives equivalent thereto are within the spirit and scope ofthe invention set forth herein.

What is claimed is:
 1. A method of decreasing the permeability of dentincomprising applying to the dentin an effective amount of oxalic acidpotassium salt, dihydrate in an aqueous solution, the concentration ofthe oxalic acid potassium salt dihydrate ranging from about 1.5% about10.0% by weight and the solution having a pH in the range of about 2.0to about 4.0.
 2. The method of claim 1 wherein the effective amount ofoxalic acid potassium salt dihydrate is 2.9%.
 3. The method of claim 1wherein the pH of the solution containing the oxalic acid potassium saltdihydrate is 3.0.
 4. A method of desensitizing hypersensitive dentin andcementum comprising applying to the dentin and cementum an effectivedesensitizing amount of oxalic acid potassium salt, dihydrate in anaqueous solution, the concentration of the oxalic acid potassium saltdihydrate being about 1.5% to about 10% by weight and the solutionhaving a pH in the range of about 2.0 to about 4.0.
 5. The method ofclaim 4 wherein the amount of the oxalic acid potassium salt dihydrateis 2.9%.
 6. The method of claim 4 wherein the pH of the oxalic acidpotassium salt dihydrate solution is 4.0.
 7. A method of diagnosingreversible and irreversible dentinal pain in a patient with a dentalrestoration, the restoration having an interface with the tooth,comprising applying a solution of oxalic acid potassium salt dihydrateonto and around the cavosurface margins of the tooth restorationinterface and having the patient indicate if there has been a stoppageof dentinal pain, the stoppage of the pain confirming reversible pulpinflammation in the tooth.
 8. The method of claim 7 wherein theeffective amount of oxalic acid potassium salt dihydrate ranges fromabout 1.5% to about 10% by weight.
 9. The method of claim 7 wherein thesolution containing the oxalic acid potassium salt dihydrate has a pHranging from about 2.0 to about 4.0.
 10. A method of forming a solutionof oxalic acid potassium salt dihydrate comprising: admixing aneffective amount of oxalic acid potassium salt dihydrate crystals inwater; ultrasonically vibrating the solution for an effective time andfrequency to dissolve the crystals.
 11. The method of claim 10 whereinthe effective amount of oxalic acid potassium salt dihydrate is theamount needed to form a solution that desensitizes dentin and cementumand decreases the permeability of a prepared cavity surface in a tooth.12. The method of claim 11 wherein the amount of oxalic acid potassiumsalt dihydrate is about 1.5% to about 10% by weight in the finalproduct.
 13. The method of claim 12 wherein the amount of oxalic acidpotassium salt dihydrated is about 2.9% by weight in the final product.14. The method of claim 10 wherein the pH of the solution is about 2.0to 4.0.
 15. The method of claim 14 wherein the pH of the solution isabout 3.0
 16. The method of claim 10 wherein the particle size of thecrystals is indicated by not being visible by the naked eye about 24hours after formation of the solution.
 17. The method of claim 16wherein the particle size of the crystals is about 1 micron to about 10microns when the solution is viewed through a 100 power microscope. 18.The method of claim 16 wherein the particle size of the crystals isabout 1 to about 4 microns.
 19. The method of claim 11, wherein theoxalic acid potassium salt dihydrate is heated in an aqueous solutionprior to ultrasonic disassociation or vibration.
 20. The method of claim19 wherein the oxalic acid potassium salt dihydrate solution is heatedto a temperature ranging from about 850 to about 100° F.
 21. The methodof claim 20 wherein the oxalic acid potassium salt dihydrate solution isheated and mixed for a sufficient amount of time for a suspension toform.
 22. The method of claim 21 wherein the oxalic acid potassium saltdihydrate solution, in a volume of 1 liter, is heated and mixed forabout 40 minutes prior to ultrasonic disassociation.
 23. The method ofclaim 10 wherein the water is purified.
 24. The method of claim 10wherein the water is double distilled and de-ionized.
 25. The method ofclaim 10 wherein the solution is vibrated in a sonifier.
 26. The methodof claim 10 wherein the sonifier vibrates the solution at an energylevel up to 20,000 Hz.
 27. The method of claim 10 wherein the solutionis vibrated at an energy level of about 16,000 Hz to about 19000 Hz. 28.The method of claim 27 wherein the solution is vibrated at an energylevel of about 18,000 HZ.
 29. The method of claim 26 wherein thesolution is vibrated for about 30 minutes.
 30. A stable, liquidcomposition of oxalic acid potassium salt dehydrated comprising: aneffective amount of water; an effective amount of oxalic acid potassiumsalt dihydrate to decrease the permeability of dentin in solution in thewater.
 31. The liquid composition of claim 30 wherein the oxalic acidpotassium salt dihydrate has a particle size that is not visible by theunaided eye about 24 hours after the formation of the liquidcomposition.
 32. The liquid composition of claim 30 wherein the particlesize of the oxalic acid potassium salt dihydrate is about 1 to 10microns when the liquid composition is viewed through a 100 powermicroscope.
 33. The liquid composition of item 32 wherein the particlesize of the oxalic acid potassium salt dihydrate is about 1 to about 4microns when the liquid composition is viewed through a 100 powermicroscope.
 34. The liquid composition of claim 30 wherein the amount ofoxalic acid potassium salt dihydrate is about 1.5% to about 10% byweight of the composition.
 35. The liquid composition of claim 30wherein the amount of oxalic acid potassium salt dihydrate is about 2.9%by weight of the composition.
 36. The liquid composition of claim 30wherein the pH is about 2.0 to 4.0.
 37. The liquid composition of claim30 wherein the pH is about 3.0.